Late-Glacial and Holocene Pollen Diagrams from Jasiel in the Low Beskid Mts
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ACTA PALAEOBOTANICA 27 (1): 9-26, 1987 K. SZCZEPANEK LATE-GLACIAL AND HOLOCENE POLLEN DIAGRAMS FROM JASIEL IN THE LOW BESKID MTS. (THE CARPATHIANS) P6inoglacjalny i holocenski profil pylkowy z Jasiela w Beskidzie Niskim (Karpaty) ABSTRACT. Material obtained from the cores of peatbog sediments, ca 2 m in thickness,. taken in the Dukla Mts. (Low Beskids, Carpathians), was used for pollen analyses. Six selected levels were dated by the 14C method. These data are used to present the vegetational changes. of the peatbog surroundings since IO 300 B. P. PRESENT-DAY NATURAL ENVIRONMENT Characteristics of the region The Low Beskid Mts. constitute the lowest and narrowest part of the Car pathian arch (Klimaszewski 1935; Starke! 1972). Tbey are ca 1830 km' in area and ca 100 km long, whereas the greatest width is up to ca 30 km. The boundary between the Western and Eastern Carpathians runs in this region. The system of mountain ridges extends as a rule in a SE-NW direction. The region is characterized by a very complex mosaic of orographic forms. The highest peak, situated close to the western boundary of the area, rises to an altitude of 999 m. Except for one other peak, which reacbes 996 m, no mountain top attains 900 m. The highest mountains are grouped at the opposite ends of the range, which extends in the direction of the parallel of latitude. The lowest floors of the valleys lie at an altitude of 300 m. Out of the numerous ranges of the Low Beskids, the Dukla Mts., lying in the central part of the region, are tbe lowest. Here the culminations of i•idges and hills reach altitudes from 520 to 720 m. The Dukla Pass (502 m a.s.l.), which is the lowest in the whole Carpathian arch, is situated in this area. The southern summits mark the European wate... shed, separating the catchment area of the Baltic Sea from that of the Black Sea. ~ ( lllJTT llt.&Wi1t;1 tt \ ' 10 The geological structure of the Low Beskid Mts. is also very complex. They are built of rocks belonging to the Carpathii'!,n flysch, Lower Cretaceous-Oligo cene in age. Five main stratigraphic-tectonic units have been distinguished here: the Magura nappe, Dukla folds, Silesian nappe, sub-Silesian nappe and the Skolska nappe. The morphology of the region reflects the basic stratigraphic -tectonic elements and the varied resistance of rocks to weathering. The higher parts of mountains are mostly of the Magura series and Dukla folds. These rocks are the poorest in alkali compounds and calcium carbonate. As regards mor phology, the rocks richer in calcium carbonate are characterized by a lower and gentler relief. The rocky substratum is strongly folded and jointed throughout the Low Beskid Mts. (Swidzinski 1953; Starke! 1972). In the SE-NW elevations both inclination and degree of scaliness of the main rock formations increase regularly. As a result, the northern and western slopes are generally more humid (and wooded) than the southern and eastern slopes. The Quaternary covers consist chiefly of loamy-stony or clayeystone col luvial and solifluctional sediments, 10-30 m tli~ck, overlying tbe slopes. The valleys are filled with fluvial sediments. Diversified acid and leached brown loamy soils, occupy the greater part of the L(}W Beskid area. In the mountain ranges they are usually of a medium thickness (up to 50 cn:1) with a consideru.ble skeleton content (especially where more resistant sandstones occur in the substratum). Soils of this type, occurring on slopes and notably under crops, are exposed to intense processes of deflation. Bro"' n soils, reddish-brown soils, pai·arendzinas, podsols proper, initial hydro genic soils and others appear more rarely. The leading factor that effects the climatic conditions in the Low Beskid 1\fts. is the relief. The intensity of the mountain climate increa.ses from the piedmont regions towards the highest ranges. In accordance with the classification of the climate of the Polish Western Carpathians (Hess 1965), two climatic zones can be distinguished in this area: a moderately warm zone, with mean tempera tures, calculated for many years, lying between 6 and 8°C, and a moderately cool zone with mean temperatures from 4 to 6°C. In this region the boundary between these two zones runs at an altitude of 500-570 rn. The zones represent a pluvial type of climate and the whole area belongs to the Carpathian climatic province (Guminski 1950). Fairly big differences in mean annual rainfall from ca 700 to ca 900 mm occurring between particular areas are dependent on the relief and altitude. The region under discussion is characterized by the occurrence of strong southern foehn-typ€ winds blowing from over the Hungarian Lowland. These winds are most frequent in late autumn, ia winter, and in early spring, occurring more rarely in summer. They bring about great anomalies in the prevailing weatlier. In the Low Beskid Mts. the growing season lasts from 215 days in the valleys to 182 days on the summits (Hess 1965, Hess et al. 1976). 11 The flora. of the Low Beskid Mts. is relatively poor. This is due to their small and weakly differentiated altitudes, and the uniformity of the geologic substratum. At present woods cover 35-50% of the total area here (Swi~s 1980, 1982). The most intensely wooded parts are the highest mountain ridges at the opposite ends of the Low Beskid w11ge. l\fosotrophic communities prevail in its plant cover. The forest communities show the most distinct differentiation according to altitude. Two vegetational zones have been distinguished here: the foothills zone and lower montane forest zone. Remnants of the hornbeam forest (Tilio-Carpinetum) occur in the foothill zone, whereas the beech forests (Dentario glandulosae-Fagetum), not very widespread acidophilous fir forests, beech forests with V accini1im myrtillus and fragments of other forest communities make up tbe lower montane forest zone. Alder woods (Alnetum incanae) predominate in the river and stream valleys. Both self-sown and planted woods and thickets composed of Alnits incana, Pinus sylvestris and Juniperus communis occur generally on the now uncultivated ground. Apart from the natural meadow communities of the orders Arrhena.theretalia and Molinietalia, large are::i.s are occupied by semi-uatural meadows and sy nanthropic communities undefinable phytosociologically (Sw i~s 1980, 1982; Grodzinsk!a 1968; Grodzinska & Pancer-Kotejo"' a 1965). The nearly co1nplete disappearance of the western Carpathian species and the so mewhat slower disappearance of the eastern Carpathian species are a charac teristic botanical feature of this area. In the botanical division of Poland, this mountain range is distinguished as a separate sub-region and with respect to flora it is intermediate between the west and east Carpathians (Pawlowski 1972). The beginnings of the colonization of the Low Beskids by fairly numerous groups of people from the circle of the Corded Ware Culture took place as late as the Younger Neolithic. The popufation increased in the Bronze Age, at the time of the development of the Protoslav Lusatian Culture (Sulimirski 1957, 1959; Machnik 1960, 1962; Zaki 1955). Colonization occurred chiefly in dells and larger river valleys and included communities whose husbandry was mainly based on cattle breeding and pasturage. The region became densely populated as late as the early a,nd late Middle Ages, or in the 13th-15th cc. On the turns of the 14th and 15th century the nomadic-pastoral and pastoral-agricultural population contributed to the devastation of the natura1 forests in nearly all convenient places in the mountains. This was responsible for marked changes in the local water and microclimatic conditions, increased floods, the deepening of river channels and valleys, drying of slopes, etc. Owing to the considerable depopulation of this area after 1947, fields, meadows and pastures have been turned into swamps, and succession mainly of Alnus incana,, Betula verrucosa and semi-natural herb communities have developed. 12 Des~ription of the• site The material used for the palynological study comes from a peatbog situated about 20 km to the south-east of Dukla, in the south-eastern part of the Dukla Mts. (49°22'22" N, 21° 53'13" E), close to the state frontier. The nearest villages, Jasiel and Rudawka Jasliska, are at 9J distance of 3-5 km. The peatbog is 10 hectares in area ~md lies at an altitude of about 670-680 m; it is below the summit of a hill o.a its side slopiug at about 5° northeastnorth ward. It is in the headwaters of a small stream - a left-bank tributary of the Jasiolka (Fig. 1). The peat layer is on the average 1 m thick, the maximum thickness Fig. I. 1\fap showing the location of .Jasiel mire of the organogenic sediment being about 2 m. The pea.tbog was d.rained by several ditches. On its surface there gi.·ow clumps of Salix sp. div., Alnus gluti nosa, A. incana, Betula verrucosa, Frangula alnus, J uniperus commitnis, V acci nium vitis-idaea, V. myrtillus and above all Phragmites communis and .21:folinia coerulea, which form large groups. Mosses of the genera Sphagnum and Poly trichum overgrow small areas forming a mosaic. Degraded meadow (pasture) communities on a minei·al substratum extend south and west of the peatbog. In the north and east a dense fir-beech forest comes near the edge of the peatbog. In the north the peatbog is drained by several streamlets which dissect the pro jecting rocky bank supporting the sediment layers lying at the bottom of the peatbog. The peatbog is situated within tbe lower montane forest zone with 13 beech and fir-beech forests now prevailing.